Information About vEthernet Interfaces

Virtual Ethernet (vEthernet or vEth) interfaces are logical interfaces. Each vEthernet interface corresponds to a switch interface that is connected to a virtual port. The interface types are as follows:

VM (interfaces connected to VM NICs)

Service console

vmkernel

vEthernet interfaces are created on the Cisco Nexus 1000V to represent virtual ports in use on the distributed virtual switch.

vEthernet interfaces are mapped to connected ports by MAC address as well as DVPort number. When a server administrator changes the port profile assignment on a vNIC or hypervisor port, the same vEthernet interface is reused.

When bringing up a vEthernet interface where a change in the port profile assignment is detected, the Virtual Supervisor Module (VSM) automatically purges any manual configuration present on the interface. You can use the following command to prevent purging of the manual configuration:

no svs veth auto-config-purge

Guidelines and Limitations

vEthernet interface configuration has the following configuration guideline and limitation:

MTU cannot be configured on a vEthernet interface.

Default Settings

Table 1 Default Settings for vEthernet Interface

Parameters

Default

Switchport mode

Access

Allowed VLANs

1 to 4094

Access VLAN ID

VLAN1

Native VLAN ID

VLAN1

Native VLAN ID tagging

Disabled

Administrative state

Shut

Automatic deletion of vEthernet interfaces

Enabled

Automatic purge of manual configuration on vEthernet interfaces

Enabled

Automatic creation of vEthernet interfaces

Enabled

Configuring vEthernet Interfaces

Configuring Global vEthernet Properties

You can enable or disable the following automatic controls for vEthernet interfaces:

Deleting unused vEthernet interfaces

Purging of manual vEthernet configurations

Creating vEthernet interfaces

Before You Begin

Log in to the CLI in EXEC mode.

Procedure

Command or Action

Purpose

Step 1

switch# configure terminal

Enters global configuration mode.

Step 2

switch(config)# [no] svs veth auto-delete

(Optional)

Enables the VSM to automatically delete DVPorts no longer used by a vNIC or hypervisor port.

The default setting is enabled.

The no form of this command prevents the VSM from deleting unused DVPorts.

Step 3

switch(config)# [no] svs veth auto-config-purge

(Optional)

Enables the VSM to remove all manual configuration on a vEthernet interface when the system administrator changes a port profile on the interface.

The default setting is enabled.

The no form of this command prevents the manual configuration from being deleted in this situation.

Note

Port profiles with ephemeral bindings are purged regardless of this setting.

Step 4

switch(config)# [no] svs veth auto-setup

(Optional)

Enables the VSM to automatically create a vEthernet interface when a new port is activated on a host.

The no form of this command disables the automatic creation of vEthernet interfaces in this situation.

Note

You can use no form of the command to temporary block automatic creation of vEthernet interfaces.

Step 5

switch(config)# show running-config all | grep“svs-veth”

(Optional)

Displays the default global vEthernet settings that are in effect on the VSM for verification. If a setting is disabled, it does not display in the show command output.

Step 6

switch(config)# copy running-config startup-config

(Optional)

Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

Configuring a vEthernet Access Interface

You can configure a vEthernet interface for use as an access interface.

Before You Begin

Log in to the CLI in EXEC mode.

If you do not add a description to the vEthernet interface, one of the following descriptions is added at attach time. If you add a description and then remove it using the no description command, then one of the following descriptions is added to the interface: